We intend to continue our studies into the regulation of membrane transport function in muscle and ascites cells. Studies focusing on the sarcoplasmic reticulum of frog muscle will include the application of the techniques of compartmental analysis and autoradiography to Ca release during excitation-contraction coupling. Techniques will be developed for the accurate assessment of insulin binding and metabolic effect in mouse diaphragms. The efficacy of the flux ratio method for the determination of the membrane potential in ascites cells will be assessed.